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<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN"><html><head><meta name="generator" content="HTML Tidy, see www.w3.org"><meta http-equiv="Content-Type" content="text/html; charset=iso-8859-1"><link type="text/css" rel="stylesheet" href="style.css"><!-- Generated by The Open Group's rhtm tool v1.2.1 --><!-- Copyright (c) 2001-2003 The Open Group, All Rights Reserved --><title>Definitions</title></head><body bgcolor="white"><basefont size="3"> <!--header start--><center><font size="2">The Open Group Base Specifications Issue 6<br>IEEE Std 1003.1, 2003 Edition<br>Copyright © 2001-2003 The IEEE and The Open Group, All Rights reserved.</font></center><!--header end--><hr size="2" noshade><h2><a name="tag_03"></a>Definitions</h2><p>For the purposes of IEEE Std 1003.1-2001, the terms and definitions given in <a href="#tag_03">Definitions</a> apply.<basefont size="2"></p><dl><dt><b>Note:</b></dt><dd>No shading to denote extensions or options occurs in this chapter. Where the terms and definitions given in this chapter areused elsewhere in text related to extensions and options, they are shaded as appropriate.</dd></dl><basefont size="3"> <h3><a name="tag_03_01"></a>Abortive Release</h3><p>An abrupt termination of a network connection that may result in the loss of data.</p><h3><a name="tag_03_02"></a>Absolute Pathname</h3><p>A pathname beginning with a single or more than two slashes; see also <a href="#tag_03_266">Pathname</a> . <basefont size="2"></p><dl><dt><b>Note:</b></dt><dd>Pathname Resolution is defined in detail in <a href="xbd_chap04.html#tag_04_11"><i>Pathname Resolution</i></a> .</dd></dl><basefont size="3"> <h3><a name="tag_03_03"></a>Access Mode</h3><p>A particular form of access permitted to a file.</p><h3><a name="tag_03_04"></a>Additional File Access Control Mechanism</h3><p>An implementation-defined mechanism that is layered upon the access control mechanisms defined here, but which do not grantpermissions beyond those defined herein, although they may further restrict them. <basefont size="2"></p><dl><dt><b>Note:</b></dt><dd>File Access Permissions are defined in detail in <a href="xbd_chap04.html#tag_04_04"><i>File Access Permissions</i></a> .</dd></dl><basefont size="3"> <h3><a name="tag_03_05"></a>Address Space</h3><p>The memory locations that can be referenced by a process or the threads of a process.</p><h3><a name="tag_03_06"></a>Advisory Information</h3><p>An interface that advises the implementation on (portable) application behavior so that it can optimize the system.</p><h3><a name="tag_03_07"></a>Affirmative Response</h3><p>An input string that matches one of the responses acceptable to the <i>LC_MESSAGES</i> category keyword <b>yesexpr</b>, matchingan extended regular expression in the current locale. <basefont size="2"></p><dl><dt><b>Note:</b></dt><dd>The <i>LC_MESSAGES</i> category is defined in detail in <a href="xbd_chap07.html#tag_07_03_06"><i>LC_MESSAGES</i></a> .</dd></dl><basefont size="3"> <h3><a name="tag_03_08"></a>Alert</h3><p>To cause the user's terminal to give some audible or visual indication that an error or some other event has occurred. When thestandard output is directed to a terminal device, the method for alerting the terminal user is unspecified. When the standardoutput is not directed to a terminal device, the alert is accomplished by writing the <alert> to standard output (unless theutility description indicates that the use of standard output produces undefined results in this case).</p><h3><a name="tag_03_09"></a>Alert Character (<alert>)</h3><p>A character that in the output stream should cause a terminal to alert its user via a visual or audible notification. It is thecharacter designated by <tt>'\a'</tt> in the C language. It is unspecified whether this character is the exact sequence transmittedto an output device by the system to accomplish the alert function.</p><h3><a name="tag_03_10"></a>Alias Name</h3><p>In the shell command language, a word consisting solely of underscores, digits, and alphabetics from the portable character setand any of the following characters: <tt>'!'</tt> , <tt>'%'</tt> , <tt>','</tt> , <tt>'@'</tt> .</p><p>Implementations may allow other characters within alias names as an extension. <basefont size="2"></p><dl><dt><b>Note:</b></dt><dd>The Portable Character Set is defined in detail in <a href="xbd_chap06.html#tag_06_01"><i>Portable Character Set</i></a> .</dd></dl><basefont size="3"> <h3><a name="tag_03_11"></a>Alignment</h3><p>A requirement that objects of a particular type be located on storage boundaries with addresses that are particular multiples ofa byte address. <basefont size="2"></p><dl><dt><b>Note:</b></dt><dd>See also the ISO C standard, Section B3.</dd></dl><basefont size="3"> <h3><a name="tag_03_12"></a>Alternate File Access Control Mechanism</h3><p>An implementation-defined mechanism that is independent of the access control mechanisms defined herein, and which if enabled ona file may either restrict or extend the permissions of a given user. IEEE Std 1003.1-2001 defines when such mechanismscan be enabled and when they are disabled. <basefont size="2"></p><dl><dt><b>Note:</b></dt><dd>File Access Permissions are defined in detail in <a href="xbd_chap04.html#tag_04_04"><i>File Access Permissions</i></a> .</dd></dl><basefont size="3"> <h3><a name="tag_03_13"></a>Alternate Signal Stack</h3><p>Memory associated with a thread, established upon request by the implementation for a thread, separate from the thread signalstack, in which signal handlers responding to signals sent to that thread may be executed.</p><h3><a name="tag_03_14"></a>Ancillary Data</h3><p>Protocol-specific, local system-specific, or optional information. The information can be both local or end-to-end significant,header information, part of a data portion, protocol-specific, and implementation or system-specific.</p><h3><a name="tag_03_15"></a>Angle Brackets</h3><p>The characters <tt>'<'</tt> (left-angle-bracket) and <tt>'>'</tt> (right-angle-bracket). When used in the phrase"enclosed in angle brackets", the symbol <tt>'<'</tt> immediately precedes the object to be enclosed, and <tt>'>'</tt>immediately follows it. When describing these characters in the portable character set, the names <less-than-sign> and<greater-than-sign> are used.</p><h3><a name="tag_03_16"></a>Application</h3><p>A computer program that performs some desired function.</p><h3><a name="tag_03_17"></a>Application Address</h3><p>Endpoint address of a specific application.</p><h3><a name="tag_03_18"></a>Application Program Interface (API)</h3><p>The definition of syntax and semantics for providing computer system services.</p><h3><a name="tag_03_19"></a>Appropriate Privileges</h3><p>An implementation-defined means of associating privileges with a process with regard to the function calls, function calloptions, and the commands that need special privileges. There may be zero or more such means. These means (or lack thereof) aredescribed in the conformance document. <basefont size="2"></p><dl><dt><b>Note:</b></dt><dd>Function calls are defined in the System Interfaces volume of IEEE Std 1003.1-2001, and commands are defined in theShell and Utilities volume of IEEE Std 1003.1-2001.</dd></dl><basefont size="3"> <h3><a name="tag_03_20"></a>Argument</h3><p>In the shell command language, a parameter passed to a utility as the equivalent of a single string in the <i>argv</i> arraycreated by one of the <i>exec</i> functions. An argument is one of the options, option-arguments, or operands following the commandname. <basefont size="2"></p><dl><dt><b>Note:</b></dt><dd>The Utility Argument Syntax is defined in detail in <a href="xbd_chap12.html#tag_12_01"><i>Utility Argument Syntax</i></a> andthe Shell and Utilities volume of IEEE Std 1003.1-2001, <a href="../utilities/xcu_chap02.html#tag_02_09_01_01">Section2.9.1.1, Command Search and Execution</a>.</dd></dl><basefont size="3"> <p>In the C language, an expression in a function call expression or a sequence of preprocessing tokens in a function-like macroinvocation.</p><h3><a name="tag_03_21"></a>Arm (a Timer)</h3><p>To start a timer measuring the passage of time, enabling notifying a process when the specified time or time interval haspassed.</p><h3><a name="tag_03_22"></a>Asterisk</h3><p>The character <tt>'*'</tt> .</p><h3><a name="tag_03_23"></a>Async-Cancel-Safe Function</h3><p>A function that may be safely invoked by an application while the asynchronous form of cancellation is enabled. No function isasync-cancel-safe unless explicitly described as such.</p><h3><a name="tag_03_24"></a>Asynchronous Events</h3><p>Events that occur independently of the execution of the application.</p><h3><a name="tag_03_25"></a>Asynchronous Input and Output</h3><p>A functionality enhancement to allow an application process to queue data input and output commands with asynchronousnotification of completion.</p><h3><a name="tag_03_26"></a>Async-Signal-Safe Function</h3><p>A function that may be invoked, without restriction, from signal-catching functions. No function is async-signal-safe unlessexplicitly described as such.</p><h3><a name="tag_03_27"></a>Asynchronously-Generated Signal</h3><p>A signal that is not attributable to a specific thread. Examples are signals sent via <a href="../functions/kill.html"><i>kill</i>()</a>, signals sent from the keyboard, and signals delivered to process groups. Beingasynchronous is a property of how the signal was generated and not a property of the signal number. All signals may be generatedasynchronously. <basefont size="2"></p><dl><dt><b>Note:</b></dt><dd>The <a href="../functions/kill.html"><i>kill</i>()</a> function is defined in detail in the System Interfaces volume ofIEEE Std 1003.1-2001.</dd></dl><basefont size="3"> <h3><a name="tag_03_28"></a>Asynchronous I/O Completion</h3><p>For an asynchronous read or write operation, when a corresponding synchronous read or write would have completed and when anyassociated status fields have been updated.</p><h3><a name="tag_03_29"></a>Asynchronous I/O Operation</h3><p>An I/O operation that does not of itself cause the thread requesting the I/O to be blocked from further use of theprocessor.</p><p>This implies that the process and the I/O operation may be running concurrently.</p><h3><a name="tag_03_30"></a>Authentication</h3><p>The process of validating a user or process to verify that the user or process is not a counterfeit.</p><h3><a name="tag_03_31"></a>Authorization</h3><p>The process of verifying that a user or process has permission to use a resource in the manner requested.</p><p>To ensure security, the user or process would also need to be authenticated before granting access.</p><h3><a name="tag_03_32"></a>Background Job</h3><p>See <i>Background Process Group</i> in <a href="#tag_03_34">Background Process Group (or Background Job)</a> .</p><h3><a name="tag_03_33"></a>Background Process</h3><p>A process that is a member of a background process group.</p><h3><a name="tag_03_34"></a>Background Process Group (or Background Job)</h3><p>Any process group, other than a foreground process group, that is a member of a session that has established a connection with acontrolling terminal.</p><h3><a name="tag_03_35"></a>Backquote</h3><p>The character <tt>'`'</tt> , also known as a grave accent.</p><h3><a name="tag_03_36"></a>Backslash</h3><p>The character <tt>'\'</tt> , also known as a reverse solidus.</p><h3><a name="tag_03_37"></a>Backspace Character (<backspace>)</h3><p>A character that, in the output stream, should cause printing (or displaying) to occur one column position previous to theposition about to be printed. If the position about to be printed is at the beginning of the current line, the behavior isunspecified. It is the character designated by <tt>'\b'</tt> in the C language. It is unspecified whether this character is theexact sequence transmitted to an output device by the system to accomplish the backspace function. The <backspace> definedhere is not necessarily the ERASE special character. <basefont size="2"></p><dl><dt><b>Note:</b></dt><dd>Special Characters are defined in detail in <a href="xbd_chap11.html#tag_11_01_09"><i>Special Characters</i></a> .</dd></dl><basefont size="3"> <h3><a name="tag_03_38"></a>Barrier</h3><p>A synchronization object that allows multiple threads to synchronize at a particular point in their execution.</p><h3><a name="tag_03_39"></a>Base Character</h3><p>One of the set of characters defined in the Latin alphabet. In Western European languages other than English, these charactersare commonly used with diacritical marks (accents, cedilla, and so on) to extend the range of characters in an alphabet.</p>⌨️ 快捷键说明
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